In certain photofinishing equipment there is provided a removable magazine upon which finished photosensitive material is placed. The magazine is designed to interface with the photofinishing equipment so that a light tight seal is formed therebetween. In such devices it is paramount that this light tight seal be maintained. In order to achieve this seal there is often provided a complex geometric interface between the magazine and the equipment. This requires that the removable magazine be positioned at a specific location. It is also necessary to align a drive mechanism with the magazine core so that rotary motion may be properly transferred to the core. Frequently a conflict occurs between the magazine positioning requirements of the light lock and the requirements to align the axis of the drive shaft to the magazine core. Since the light lock requirement is paramount, a coupling is provided for allowing proper engagement.
One prior art coupling utilizes two pins extending axially from a hub. The pins are parallel and are disposed at equal distances from the rotational axis of the hub. Cooperating with the pins is a bar mounted on an axially adjacent hub mounted so as to extend intermediate the two pins so that rotational movement from one hub will drive the other hub rotationally. Such constructions have several disadvantages.